273 vs 318 [in England!]

Helllo from the United Kingdom

I have a choice to purchase a 69 273 Dart or a 71 318 Dart Swinger. I live in England - for the cars themselves check this site; http://www.madders.freeserve.co.uk/mainpage.html [might seem pricey- but bear in mind shipping costs, import duties and profit]
I actually prefer the styling of the 69 in a lot of ways but reckon a 71 with a 318 might be a sweeter drive.
Price of petrol here [£5 - or 10 US dollars a gallon] means outright performance won't be a priority for the future- just a set of duels to make it sound right.
I'm just interested if there are any particular problems or advantages with either of these models- they are pretty rare over here.

Cheers for any advice

Nick.